**Core Concept**
Total lung capacity (TLC) is the maximum volume of air present in the lungs after maximum inspiration. It represents the sum of vital capacity, residual volume, and the volume of air in the airways.

**Why the Correct Answer is Right**
The correct answer is the factor that directly influences the maximum expansion of the lungs. TLC is significantly affected by lung volume and the elastic recoil of the lungs and chest wall. The correct answer is the component that determines the maximum lung expansion.

**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because lung compliance is the ability of the lungs to expand in response to changes in pressure. While compliance affects lung volume, it's not the primary determinant of TLC.

**Option B:**
This option is incorrect because airway resistance is the opposition to airflow in the airways. Although airway resistance affects the ease of breathing, it does not directly influence TLC.

**Option C:**
This option is incorrect because the diaphragm is the primary muscle of inspiration, but its role is to increase the volume of the thoracic cavity, not directly affect TLC.

**Clinical Pearl / High-Yield Fact**
Lung volumes and capacities are significantly affected by the balance between the elastic recoil of the lungs and the chest wall. A decrease in lung compliance can lead to a reduction in TLC.

**Correct Answer: D. Lung volume.**